Improvement in steam-generators



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' boilers.

UNrrn STATES 'PATENT OFFICE@ R. RAFAEL, OF NEW YORK, N. Y.

llVl PROVEM ENT IN STEAM-GENERATORS.

Specification forming part of Letters Patent No. 5,205, dated April 24, 1866.

To all 'whom it'may concern:

Be it known that I, R. RAFAEL, of the city, county, and State of New York, have invented a new and Improved Steam-Boiler; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which Figure l represents a longitudinal vertical section of this invention. Fig. 2 is a transverse vertical section of the same. Fig. 3 is a longitudinal section of a modiiication of the same. Fig. 4 is a similar view of another modification of the same.

Similar letters of reference indicate like parts.

This vinvention* consists in placing the furnace or lire-place of a vsteam-boiler at or nea-r the top of the same in such a manner as to have there the highest heat, causing at the same time the hot gases to descend towa-rd the bottom ofthe boiler, either in a zigzag direction or otherwise. By these means different degrees of heat are produced in the water, the highest degreesbeing always on the top and the lowest at the bottom of the boiler, and

consequently no circulation of the water will take place, as in ordinary boilers, whether the water is made to pass through the tubes or outside of them, and whether those tubes are placed horizontal, vertical, or in any other convenient position; and, furthermore, the heated gases being brought in contact with water of gradually-decreasing temperature, will be deprived of all their heat, or nearly so, before they are allowed to escape through the chimncy.

The great waste of fuel in the opera-tion of steam-engines is not owing simply to the imperfection of the engine itself, but in a much greater measure to the imperfection of the If the quantity of heat inthe furnace be computed, it will be found that but a very small portion of it enters the boiler to produce steam, the greatest part escaping up the chimney being wasted into the open atmosphere. This great waste of heat is well known to all engineers, and it can be easily demonstrated that the same cannot be avoided in steam-boilers as at present constructed. Whatever be their peculiar arr ngements, their principle is invariably this: To have within them a body which takes place in the boiler, bearing always.

in mind the law ot' the'equilibrium of temperatures, according to which a circulating gas will impart heat to the body through which it circulates provided its temperature is higher than that ot' said body; but it will absorb heat from said body if its temperature be lower.

The boiler being full ot' water and the iire lightedinthefurnace,thehotgasesissuingfrom the lire begin to circulate,-and as the temperature of the water and the iron surrounding it is so much lower than that ot' the. gases the heat, in its tendency for an equilibrium, parts from the gases and enters the iron and the water. In this state of thc case if the heatingsurface of the boiler were sufficient] y large, the whole heat generated in the furnace would be absorbed by the water, and the gases at their point of eXit in the chimney would be found comparatively cold. But this would last only one moment. The heat from the gases passing into the iron and the water would raise their temperature gradually, and just in proportion as this temperature would increase the passage of heat from the gases to the water would diminish, such passage being possible only as long as the temperature ofthe gases exceeds that of the water. As the difference in the temperature of the gases and of the water diminishes the passage of the'heat from the gases into the water diminishes in the same proportion; and ifa thermometer be placed at the point where the gases leave the boiler and enter the chimney, it will be found that their temperature, instead of being almost cold, as at the beginning of the operation, has increased just in proportion to that of the Water in the boiler. This process continues, but at every successive moment the temperature of the water being higher and higher, and the difference 4from the gases to the water diminishes, and

the temperature of the gases escaping up the chimney increases precisely in the same ratio. After a certain time the water will reach the highest temperature which it can possibly attain, and if it is supposed that in order to impart to the water said highest temperature the gases generated in the furnace must have a temperature of 12000; and if after the water has reached its highest temperature the temperature ofthe gases is suddenly reduced to 9000, (by the in trod uetion of fresh fuel or from some other cause,) itis evident that the temperature of the water will also be reduced in proportion, because in that case the gases, instead of imparting heat to the water, take away from it until the equilibrium is restored. During this process ot' restoring the equilibrium all the heat generated in the furnace, plus all the heat extracted by the heated gases, runs up the chimney and is a mere waste.

These disadvantages are overcome by the construction of my steam-boiler, in which all circulation of the water is avoided, and the firegrate A is so situated that the heated gases, on emanating therefrom, will rst come in contact or compartments b, or if the water is contained in a series of tubes, e, as shown in Fig. 3, said tubes are placed in a vertical position in the heating-chamber, which is provided with a series of horizontal zigzag partitions, so that the heated gases are compelled to travel in a zigzig course from the hre-place down to the bottom of the boiler, whence the same are allowed to escape into the chimney.

By Athis arrangement the greatest possible amount of the heat generated in the furnace is transferred to the water, for as this heat gradually diminishes in its passage from the furnace to the chimney, so as to mark a const-antly-deseending scale, in the same manner the water in the boiler has an equally descending scale ot still lower degrees, the coldest Water being at the bottom, and the hottest in the upper, part of the boiler, next to the lireplace.

By referring to Fig. 2 it will be noticed the ash-pit d has an inverted conical or arched form to allow the steam to pass up to the steam-chamber above with the greatest possible freedom.

R. RAFAEL.

Witnesses:

WM. T. MGNAMARA, C. L. TOPLIFF. 

